The new regulations will come into force on Friday, with police estimating about 62,000 of the blasters are circulating in the SA community.

They use compressed air to fire a projectile and often look like a real gun.

Police Firearms Branch Superintendent Stephen Howard said the firing mechanism met the threshold to be defined a firearm.

"A gel blaster can easily be mistaken for a real firearm, with potential to cause concern in the community and trigger a police response that could involve the use of police firearms, or other tactical options," Supt Howard said.

Owners who don't wish to obtain a licence can instead surrender their blasters to police or a firearms dealer under an amnesty to continue until April next year.

The changes also mean the sale of blasters will become regulated across SA.

The Shooters Union in South Australia has previously lobbied against regulating the devices.

State president Peter Heggie urged police to focus their efforts instead on educating the public about their proper use.

"These things are toys. They can't hurt anyone. They can barely break a balloon much less injure or kill people," he said.

"Our position has always been that guns should be regulated on how they work, not what they look like.

"There are already laws on the books for threatening people with imitation firearms or assault, and they're more than adequate for dealing with people who do stupid things like hold up service stations or fire gel balls at pedestrians."

Australian Associated Press